Microstructure and mechanical properties of ultrafine grain ZK60 alloy processed by equal channel angular pressing

The microstructure evolution and tensile properties of ZK60 magnesium alloy after equal channel angular pressing (ECAP) have been investigated. The results show that the two-step ECAP process is more effective in grain refinement than the single-step ECAP process due to the lower deformation temperature, a mean grain size of ~0.8 μm was obtained after two-step ECAP process at 513 K for four passes and 453 K for four passes. The EBSD examination reveals that ZK60 alloy after two-step ECAP process exhibits a more homogeneous grain size and misorientation distribution than single-step ECAP process. Both alloys after ECAP process present similar strong {0002} texture. The tensile strength of two-step ECAP alloy has also been improved compared with the single-step ECAP alloy. The strengthening effect was mainly ascribed to grain refinement.